The bacterium,isolated from pond water,that you are working with appears to use light for energy.Based upon this information,you inoculate the organism into fresh media,infused with lots of carbon dioxide.Even after incubation at the correct temperature (of pond water),the organism is not growing.Your best explanation of what might have happened is:

Question

Quizplus · Accepted Answer

Since the bacterium is known to use light for energy, it is most likely a photosynthetic organism. Photosynthetic organisms typically use a sulfur compound as an electron donor during photosynthesis. Thus, without the addition of a sulfur compound to the medium, the organism would not be able to perform photosynthesis and grow. The lack of oxygen or the wrong type of sunlight would not necessarily prevent the organism from growing in this scenario, and there is no information provided to suggest the presence of an inhibitory chemical.

The Bacterium,isolated from Pond Water,that You Are Working with Appears